据交通事故数据统计分析，汽车前碰撞引起的下肢损伤在美国造成每年超过75亿美元的损失，其中由膝盖-大腿-髋（KTH）损伤所引起的费用约占一半。目前，中国及欧美汽车碰撞安全法规中用于评估KTH损伤的股骨轴向力指标已被广泛质疑。近期研究提出了两个基本假设作为进一步探索KTH损伤容限的基础：肌肉力影响，及股骨轴向力和弯矩的联合作用。因此，本研究便是基于这两个假设，结合志愿者实验和数值仿真，研究汽车前碰撞中乘员的KTH损伤容限。研究拟耦合有限元模型及肌肉激活控制程序建立3D主动肌肉下肢-盆骨模型，并结合志愿者实验数据反求肌肉力。以此肌肉力作用为加载条件，分析不同前碰撞环境中KTH的应力变化与骨折裂纹起始，并获取相应KTH损伤容限值。最后，基于这些损伤容限值，利用数学模型耦合股骨轴向力和弯矩作用建立KTH损伤风险曲线，为汽车碰撞安全法规的制定和汽车安全性的设计提供理论基础和参考依据。

According to accident statistical analysis, lower extremity injuries due to vehicle frontal crashes in the United States cause the loss over 7.5 billion U.S. dollars each year, of which the cost of Knee-Thigh-Hip (KTH) injuries account for approximately half. The indicators of femoral axial force for assessing KTH injuries currently used in vehicle crash safety regulations of China, Europe and United States have been widely questioned. Recent studies have proposed two basic assumptions as the basis to further explore the KTH injury tolerance: the effects of the muscle force, and the combined effects of the femoral axial force and bending moment. Therefore, based on these two assumptions, this study combines volunteer experiments and numerical simulations to study the KTH injury tolerance of passengers in the vehicle frontal crash. The study plan to couple a finite element model and a procedure controlling the muscle activation to establish a lower extremity-pelvis model with 3D active muscles, then combine with volunteer experimental data to reverse the muscle force. Taking these muscle forces as loading conditions to analyze the crack initiation of the KTH fracture in various frontal impact environments, and obtain the corresponding injury tolerance values. Finally, based on these injury tolerance values, using a mathematical model of coupling femur axial force and bending moment to establish a KTH injury risk curve, to provide a theoretical basis and reference for the establishment of vehicle crash safety regulations and the design of vehicle safety performance.